This invention relates to pedalling systems for bicycles, exercise cycles and like pedalled mechanisms. More particularly, the invention provides a pedalling apparatus that fastens a cyclist's shoe to a pedal securely for all pedal strokes. The pedalling system releases the shoe from the pedal readily upon an untoward, non-pedalling movement. Further, a cyclist can intentionally couple the shoe to the pedal, and release from the pedal, easily and essentially instantaneously. Both the coupling and releasing actions are accomplished without requiring the cyclist to remove a hand from the handlebar. The invention is described, for sake of clarity, with reference to bicycle pedalling equipment, and is applicable to other pedal-driven mechanisms.
The common bicycle pedal is driven only on a downstroke by the down thrust of a cyclist's foot. The addition of toe straps and like harnesses on a pedal, to engage the cyclist's shoe, enables an upward thrust also to propel the cycle. The addition of cleats allows the cyclist to provide ankling action, in which a combination of upward and rearward forces further enhances pedalling efficiency. The inconvenience and accident hazard of toe straps and cleats have lead to other devices for fastening a cyclist's shoe to a pedal, as German Patent Specification No. DE 3,149,345 illustrates. There is still need, however, for pedalling apparatus which is safe, convenient, reliable and simple.
The forces and movements of a foot which are involved in pedalling can have up to six degrees of action. A vertical downward force of a rider's foot on a pedal is perhaps the most common action. A rider using the prior toe straps in addition can apply a vertical upward force. Toe straps also tansfer a longitudinal forward force to the pedal, and the prior cleat transfers a longitudinal backward force. A third possible action is a lateral or sideways force, which contributes little to pedalling. The remaining three actions are rotational movements which a rider's foot can undergo. Twist is rotation about a vertical axis and roll is rotation about a longitudinal axis. Bend is rotation about a lateral axis, which is the axis that extends parallel to the axis about which a pedal revolves. Pedalling desirably involves vertical and longitudinal forces, typically with a different magnitude for each direction, i.e. up, down, forward, and backward. The rider's foot in addition may bend during a full pedalling stroke, and may twist and/or roll slightly.
One problem with toe straps and the like is that the pedalling apparatus must often be clinched by hand; the cyclist must let go of the handlebar in order to actuate engagement. The removal of the cyclist's hands from the handlebar can sometimes contribute to accidents.
It is an object of this invention to provide a pedal-shoe fastening apparatus that engages readily, that maintains positive retention for all pedalling strokes, and that releases readily in response to non-pedalling foot movements and loads, both intentional and accidental. It is also an object of this invention to provide a pedalling apparatus that can be coupled and released without manual efforts.
Another object is to provide cycle pedalling apparatus of the above character which is convenient, reliable, and safe to use. It is a further object that the apparatus be capable of providing high performance cycling. The attainment of this objective calls on the apparatus to function with greater energy transfer, and correspondingly less energy dissipation, than occurs with a conventional toe strap and cleat.
Other objects of the invention will in part be obvious and will in part appear hereinafter.